Images recorded on photographic film can represent a variety of dynamic ranges found in the subjects being recorded. Dynamic range is used to describe the variety of contrasts within an image. Dynamic range can include variations in intensity among a specific color, as well as variations in color.
The dynamic range of a film negative is greater than the dynamic range available in a photographic print or in paper. When photographic film is being developed in a photo lab, the lab technician must determine which portion of the dynamic range to use from the negative. Generally, when features in one portion of the dynamic range are chosen, other details must be left out.
Areas of the image can be selectively chosen to be bring out detail in various portions of the image and to improve the detail when printing the image. This process can be long and must be performed on each different image. Image masks can be generated for selecting the portions of the dynamic range for best selecting the image detail. An image mask can be applied to a digitized image to alter the image contrasts and increase detail in areas that would normally be lost when converting the image to a photographic print or paper. Generating a mask can be performed automatically by generating an unsharp mask (USM). However, when the USM is applied to an image, the masked image that results generally has aberrations along edges. Areas around an edge within the masked image may contain undesirable portions of lightened or darkened areas. Repairing the aberrations requires a technician to manually make changes to the masked image and can take several hours when handling multiple images.